Design and Analysis of a Class of Planar Biped Robots Mechanically Coordinated by a Single Degree of Freedom

2008 ◽  
Vol 130 (10) ◽  
Author(s):  
J. McKendry ◽  
B. Brown ◽  
E. R. Westervelt ◽  
J. P. Schmiedeler
Keyword(s):  
Mechanism Design ◽  
Hybrid System ◽  
System Analysis ◽  
Control Strategies ◽  
Degree Of Freedom ◽  
Dynamic Walking ◽  
Biped Robots ◽  
Single Degree Of Freedom ◽  
Single Degree

This paper presents a method of integrating mechanism design and hybrid system analysis for the design of single-degree-of-freedom (DOF) planar biped robots that can achieve dynamic walking gaits that are stable. Reducing the DOF in a biped can result in a reduction in the complexity of the control strategies needed to enable stable walking. Although the biped designed by this procedure is restricted to a single gait, this biped may be less complex, lighter, and less costly to construct than one whose multiple DOFs are coordinated via feedback.

Single Degree-of-Freedom Modeling of the Nonlinear Vibration Response of a Machining Robot

2020 ◽  
Vol 143 (5) ◽  
Author(s):  
Yaser Mohammadi ◽  
Keivan Ahmadi
Keyword(s):  
Control Strategies ◽  
Vibration Response ◽  
Industrial Robots ◽  
Degree Of Freedom ◽  
Restoring Force ◽  
Single Degree Of Freedom ◽  
Machining Forces ◽  
Sdof System ◽  
Single Degree ◽  
Machining Robot

Abstract Highly dynamic machining forces can cause excessive and unstable vibrations when industrial robots are used to perform high-force operations such as milling and drilling. Implementing appropriate optimization and control strategies to suppress vibrations during robotic machining requires accurate models of the robot’s vibration response to the machining forces generated at its tool center point (TCP). The existing models of machining vibrations assume the linearity of the structural dynamics of the robotic arm. This assumption, considering the inherent nonlinearities in the robot’s revolute joints, may cause considerable inaccuracies in predicting the extent and stability of vibrations during the process. In this article, a single degree-of-freedom (SDOF) system with the nonlinear restoring force is used to model the vibration response of a KUKA machining robot at its TCP (i.e., machining tool-tip). The experimental identification of the restoring force shows that its damping and stiffness components can be approximated using cubic models. Subsequently, the higher-order frequency response functions (HFRFs) of the SDOF system are estimated experimentally, and the parameters of the SDOF system are identified by curve fitting the resulting HFRFs. The accuracy of the presented SDOF modeling approach in capturing the nonlinearity of the TCP vibration response is verified experimentally. It is shown that the identified models accurately predict the variation of the receptance of the nonlinear system in the vicinity of well-separated peaks, but nonlinear coupling around closely spaced peaks may cause inaccuracies in the prediction of system dynamics.

Kinematic comparison of single degree-of-freedom robotic gait trainers

2021 ◽  
Vol 159 ◽  
pp. 104258
Author(s):  
Jeonghwan Lee ◽  
Lailu Li ◽  
Sung Yul Shin ◽  
Ashish D. Deshpande ◽  
James Sulzer
Keyword(s):  
Degree Of Freedom ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Robotic Gait
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